Liquid silicate resins

Abstract

A silicate resin that is a liquid at 25° C. in the absence of any solvent is disclosed. The silicate resin has the average formula: [W] a [X] b [Y] c [Z] d , where subscript a is from greater than 0 to 0.5; subscript b is from greater than 0 to 0.5; subscript c is from 0 to 0.5; and subscript d is from greater than 0 to 0.6; with the proviso that a+b+c+d=1; and wherein W, X, Y and Z are defined siloxy units. A method of preparing the silicate resin is also disclosed.

What is claimed is: 
     
         1 . A silicate resin that is a liquid at 25° C. in the absence of any solvent, said silicate resin having the average formula:
   [W] a [X] b [Y] c [Z] d , 
 where subscript a is from 0.20 to 0.35; subscript b is from 0.1 to less than 0.4; 
 subscript c is from greater than 0 to 0.30; and subscript d is from 0.45 to 0.55; 
 with the proviso that a+b+c+d=1; and 
 wherein:
 [W] is [R 3 SiO 1/2 ], where each R is an independently selected hydrocarbyl group; 
 [X] is [R 2 SiO 1/2 (OZ)] b′ [R 2 SiO 2/2 ] b″ , where each R is independently selected and as defined above; 0≤b′≤b; 0≤b″≤b; with the proviso that b′+b″=b; and each Z is independently H, an alkyl group, or a cation; 
 [Y] is [RSi(OZ) c′ O (3-c′)/2 ], where each R is independently selected and as defined above; each Z is independently selected and as defined above; c′ is an integer from 0 to 2 and is independently selected in each siloxy unit indicated by subscript c in the silicate resin; and 
 [Z] is [Si(OZ) d′ O (4-d′)/2 ], where each Z is independently selected and as defined above, and subscript d′ is an integer from 0 to 3 and is independently selected in each siloxy unit indicated by subscript d in the silicate resin; 
 with the proviso that an average of at least one R per molecule is an ethylenically unsaturated group; 
 wherein the silicate resin has a mole percent of SiOZ moieties of from greater than 15 to 80 percent based on the total number of moles of Si in each molecule, wherein each Z is independently selected and as defined above. 
 
 
     
     
         2 . The silicone resin of  claim 1 , wherein subscripts b′ and b″ are each greater than 0, and wherein b′>b″. 
     
     
         3 . The silicate resin of  claim 1 , wherein subscript b is from 0.15 to less than 0.4. 
     
     
         4 . The silicate resin of  claim 1 , wherein subscript a is from 0.28 to 0.32; subscript b is from 0.15 to 0.3; subscript c is from 0.01 to 0.10; and subscript d is from 0.45 to 0.52. 
     
     
         5 . The silicate resin of  claim 1 , wherein each R is an alkyl group having from 1 to 6 carbon atoms, and wherein each R 1  is an alkenyl group having from 2 to 6 carbon atoms. 
     
     
         6 . The silicate resin of  claim 1 , comprising a weight percent of silicon-bonded ethylenically unsaturated groups of from greater than 0 to 10 percent by weight of the silicate resin. 
     
     
         7 . A method of preparing the silicate resin of  claim 1 , said method comprising:
 reacting an MQ resin and a silane component comprising a silane compound in the presence of a catalyst to give the silicate resin;   wherein the silane compound has the formula R 2 R 3   x SiOR 3 ) 3-x , where R 2  is as defined above, each R 3  is an independently selected alkyl group having from 1 to 4 carbon atoms, and subscript x is 0 or 1.   
     
     
         8 . The method of  claim 7 , wherein the MQ resin has formula M z Q, where z<1. 
     
     
         9 . The method of  claim 7 , wherein, in the silicate resin, subscript a is from 0.20 to 0.35; subscript b is from 0.15 to 0.3; subscript c is from greater than 0 to 0.20; and subscript d is from 0.40 to 0.55, and wherein the silane component further comprises a third silane compound having the formula R 3 Si(OR 3 ) 3  or R 2 Si(OR 3 ) 3 , where R 2  and each R 3  is independently selected and as defined above. 
     
     
         10 . The method of  claim 9 , wherein in the silicate resin, subscript a is from 0.25 to 0.35; subscript b is from 0.15 to 0.25; subscript c is from 0.05 to 0.15; and subscript d is from 0.45 to 0.52. 
     
     
         11 . The method of  claim 7 , wherein the catalyst comprises a base catalyst.